This invention relates to compounds and methods for treatment or prevention of precancerous lesions.
Each year in the United States alone, untold numbers of people develop precancerous lesions. These lesions exhibit a strong tendency to develop into malignant tumors, or cancer. Such lesions include lesions of the breast (that can develop into breast cancer), lesions of the skin (that can develop into malignant melanoma or basal cell carcinoma), colonic adenomatous polyps (that can develop into colon cancer), and other such neoplasms. Compounds which prevent or induce the remission of existing precancerous or cancerous lesions or carcinomas would greatly reduce illness and death from cancer.
For example, approximately 60,000 people die from colon cancer, and over 150,000 new cases of colon cancer are diagnosed each year. For the American population as a whole, individuals have a six percent lifetime risk of developing colon cancer, making it the second most prevalent form of cancer in the country. Colon cancer is also prevalent in Western Europe. It is believed that increased dietary fat consumption is increasing the risk of colon cancer in Japan.
In addition, the incidence of colon cancer reportedly increases with age, particularly after the age of 40. Since the mean ages of populations in America and Western Europe are increasing, the prevalence of colorectal cancer should increase in the future.
To date, little progress has been made in the prevention and treatment of colorectal cancer, as reflected by the lack of change in the five-year survival rate over the last few decades. The only cure for this cancer is surgery at an extremely early stage. Unfortunately, most of these cancers are discovered too late for surgical cure. In many cases, the patient does not experience symptoms until the cancer has progressed to a malignant stage.
In view of these grim statistics, efforts in recent years have concentrated on colon cancer prevention. Colon cancer usually arises from pre-existing benign neoplastic growths known as polyps. Prevention efforts have emphasized the identification and removal of colonic polyps. Polyps are identified by x-ray and/or colonoscopy, and usually removed by devices associated with the colonoscope. The increased use of colon x-rays and colonoscopies in recent years has detected clinically significant precancerous polyps in four to six times the number of individuals per year that acquire colon cancer. During the past five years alone, an estimated 3.5 to 5.5 million people in the United States have been diagnosed with adenomatous colonic polyps, and it is estimated that many more people have or are susceptible to developing this condition, but are as yet undiagnosed. In fact, there are estimates that 10-12 percent of people over the age of 40 will form clinically significant adenomatous polyps.
Removal of polyps has been accomplished either with surgery or fiber-optic endoscopic polypectomyxe2x80x94procedures that are uncomfortable, costly (the cost of a single polypectomy ranges between $1,000 and $1,500 for endoscopic treatment and more for surgery), and involve a small but significant risk of colon perforation. Overall, about $2.5 billion is spent annually in the United States in colon cancer treatment and prevention.
As indicated above, each polyp carries with it a chance that it will develop into a cancer. The likelihood of cancer is diminished if a polyp is removed. However, many of these patients demonstrate a propensity for developing additional polyps in the future. They must, therefore, be monitored periodically for the rest of their lives for polyp reoccurrence.
In most cases (i.e., the cases of so-called common sporadic polyps), polyp removal will be effective to reduce the risk of cancer. In a small percentage of cases (i.e., the cases of the so-called polyposis syndromes), removal of all or part of the colon is indicated. The difference between common sporadic polyps and polyposis syndromes is dramatic. Common sporadic polyp cases are characterized by relatively few polyps, each of which can usually be removed leaving the colon intact. By contrast, polyposis syndrome cases can be characterized by many (e.g., hundreds or more) of polypsxe2x80x94literally covering the colon in some casesxe2x80x94making safe removal of the polyps impossible short of surgical removal of the colon.
Because each polyp carries with it the palpable risk of cancerous development, polyposis syndrome patients invariably develop cancer if left untreated. Surgical removal of the colon is the conventional treatment. Many of these patients have undergone a severe change in lifestyle as a result of the disfiguring surgery. Patients have strict dietary restrictions, and many must wear ostomy appliances to collect their intestinal wastes.
The search for drugs useful for treating and preventing cancer is intensive. Indeed, much of the focus of cancer research today is on the prevention of cancer because therapy is often not effective and has severe side effects. Cancer prevention is important for recovered cancer patients who retain a risk of cancer reoccurrence. Also, cancer prevention is important for people who have not yet had cancer, but have hereditary factors that place them at risk of developing cancer. With the development of new genetic screening technologies, it is easier to identify those with high risk genetic factors, such as the potential for polyposis syndrome, who would greatly benefit from chemopreventive drugs. Therefore, finding such anti-cancer drugs that can be used for prolonged preventive use is of vital interest to many people.
One way to find such drugs is to screen thousands of compounds for the same biological activity found in known chemopreventive and chemotherapeutic drugs. Most such drugs are now believed to kill cancer cells by inducing apoptosis, or as sometimes referred to as xe2x80x9cprogrammed cell death.xe2x80x9d Apoptosis naturally occurs in virtually all tissues of the body, and especially in self-renewing tissues such as bone marrow, gut, and skin. Apoptosis plays a critical role in tissue homeostasis, that is, it ensures that the number of new cells produced are correspondingly offset by an equal number of cells that die. For example, the cells in the intestinal lining divide so rapidly that the body must eliminate cells after only three days in order to prevent the overgrowth of the intestinal lining.
Recently, scientists have realized that abnormalities of apoptosis can lead to the formation of precancerous lesions and carcinomas. Also, recent research indicates that defects in apoptosis play a major role in other diseases in addition to cancer. Consequently, compounds that modulate apoptosis could be used to prevent or control cancer, as well as used in the treatment of other diseases.
Unfortunately, even though known chemotherapeutic drugs may exhibit such desirable apoptosis effects, most chemotherapeutic drugs have serious side effects that prohibit their long term use, or use in otherwise healthy individuals with precancerous lesions. These side effects, which are a result of the high levels of cytotoxicity of the drugs, include hair loss, weight loss, vomiting and bone marrow immune suppression. Therefore, there is a need to identify new drug candidates for therapy that do not have such serious side effects in humans.
In the last few years, several non-steroidal anti-inflammatory drugs (xe2x80x9cNSAIDsxe2x80x9d), originally developed to treat arthritis, have shown effectiveness in inhibiting and eliminating colonic polyps. Polyps virtually disappear when the patients take the drug, particularly when the NSAID sulindac is administered. However, the prophylactic use of currently available NSAIDs, even in polyposis syndrome patients, is marked by severe side reactions that include gastrointestinal irritations and ulcerations. Once NSAID treatment is terminated due to such complications, the polyps return, particularly in polyposis syndrome patients.
Sulindac has been particularly well received among the NSAIDs for the polyp treatment. Sulindac is a sulfoxide compound that itself is believed to be inactive as an anti-arthritic agent. The sulfoxide is reported to be converted by liver enzymes to the corresponding sulfide, which is acknowledged to be the active moiety as a prostaglandin synthesis inhibitor. The sulfide, however, is associated with the side effects of conventional NSAIDs. The sulfoxide is also known to be metabolized to sulfone compound that has been found to be inactive as an inhibitor of prostaglandin synthesis but active as an inhibitor of precancerous lesions.
This invention includes both pharmaceutical compositions containing compounds and a method of treating patients with precancerous lesions by administering a pharmacologically effective amount of those compounds described below to a patient in need of such treatment. Such compositions are effective in modulating apoptosis and eliminating and inhibiting the growth of precancerous lesions and neoplasms, but are not characterized by the severe side reactions of conventional NSAIDs.
The compounds used in the treatment of this invention are believed to be effective on precancerous lesions either because they are active themselves or because they are metabolized to active derivatives.
It was unexpectedly discovered that while the compounds of this invention do not greatly inhibit prostaglandin synthesisxe2x80x94prostaglandin synthesis inhibition being a characteristic of conventional NSAIDsxe2x80x94the compounds of this invention nonetheless have antiproliferative effects on precancerous lesion cells.
As discussed above, the present invention provides a pharmaceutical composition that includes compounds of formula I below for treating a patient with precancerous lesions: 
wherein R and R1 are independently selected from the group consisting of hydrogen, hydroxy, lower alkyl and amino; or R and R1 together may be oxygen;
R2, R3 and R4 are independently selected from the group consisting of hydrogen, hydroxy, halogen, lower alkoxy, lower alkyl and alkyl mercapto;
at least two of R5, R6 and R7 are identically selected from the group consisting of hydroxy and lower alkoxy, and the third is selected from the group consisting of hydroxy, halogen, lower alkoxy, lower alky, amino and lower dialkylamino; with the proviso that when at least one of R2, R3 or R4 is lower alkoxy, then each of R5, R6 and R7 are hydroxy or lower alkoxy;
R8 is selected from the group consisting of hydrogen and lower alkyl;
o may be 0, 1 or 2; and
M is selected from the group consisting of amino, alkylamino, dialkylamino, alkoxyamino, alkenylamino, alkynylamino, hydroxyalkylamino, polyhydroxyalkyl-amino, dialkylaminoalkylamino, aminoalkylamino, arylalkylamino selected from the group consisting of benzylamino, anilino and phenylalkylamino, aminoindan, and heterocycloalkylamino where the heterocycles are selected from the group consisting of pyridinyl, piperidinyl, piperazinyl, pyrrollidinyl and N-morpholino; wherein the alkyl between the cyclic structure and the amino may be absent, and the cyclic structures may optionally be substituted with one or more of halo, alkoxy, hydroxy, amino, alkylamino, dialkylamino and sulfonamido; or M may be NRxe2x80x2Rxe2x80x3 where NRxe2x80x2 is as described above and Rxe2x80x3 is selected from alkyl, cyanoalkyl, haloalkyl, alkylamino, dialkylaminoalkyl, alkanoylalkylester and pyridinyl.
Preferably, o is 1 or 2; and M is selected from the group consisting of amino, alkylamino, dialkylamino, alkenylamino, alkynylamino, hydroxyalkylamino, dialkylaminoalkylaniino, arylalkylamino selected from the group consisting of benzylamino, anilino and phenylalkylamino, aminoindan, and heterocycloalkylamino where the heterocycles are selected from the group consisting of pyridinyl, piperidinyl, piperazinyl, and pyrrollidinyl; wherein the alkyl between the cyclic structure and the amino may be absent, and the cyclic structures may optionally be substituted with one or more of halo, alkoxy, hydroxy, amino, alkylamino and dialkylamino; or M may be NRxe2x80x2Rxe2x80x3 where NRxe2x80x2 is as described above and Rxe2x80x3 is selected from alkyl, cyanoalkyl, alkylamino, dialkylaminoalkyl and alkanoylalkylester.
More preferably, M is selected from the group consisting of alkenylamino, alkynylamino, benzylamino, and pyridinylalkylamino; wherein the cyclic structures may optionally be substituted with one or more of halo, alkoxy, hydroxy, amino, alkylamino and dialkylamino; or M may be NRxe2x80x2Rxe2x80x3 where NRxe2x80x2 is as described above and Rxe2x80x3 is selected from alkyl, alkylamino and dialkylaminoalkyl.
Even more preferably, M is selected from the group consisting of alkenylamino, alkynylamino, benzylamino, and pyridinylalkylamino; wherein the cyclic structures may optionally be substituted with one or more of halo, alkoxy, hydroxy, amino, alkylamino and dialkylamino.
Still more preferably, M is selected from benzylamino and benzylamino substituted with one or more of halo, alkoxy, hydroxy, amino, alkylamino and dialkylamino. Yet still more preferably, M is selected from the group consisting of benzylamino and benzylamino substituted with one or more of halo, alkoxy and hydroxy. Most preferably, M is benzylamino.
For other substituents of the compound of formula I, when M is at least in its even more preferred form, preferably, R and R1 are independently selected from the group consisting of hydrogen and hydroxy; at least two of R5, R6 and R7 are lower alkoxy and the third is selected from hydroxy, lower alkoxy, amino and lower dialkylamino; or each of R5, R6 and R7 are hydroxy.
More preferably, R and R1 are hydrogen; R2, R3 and R4 are independently selected from the group consisting of hydrogen, hydroxy, halogen, lower alkoxy, lower alkyl and alkyl mercapto; at least two of R5, R6 and R7 are lower alkoxy and the third is selected from hydroxy and lower alkoxy; R8 is lower alkyl; and o is 1.
Even more preferably, R5, R6 and R7 are each lower alkoxy; and R8 is methyl.
Still more preferably, R2 is selected from the group consisting of hydroxy, halogen, lower alkoxy and alkyl mercapto; R4 is hydrogen; and R5, R6 and R7 are each methoxy.
Yet still more preferably, R2 is selected from the group consisting of hydroxy, halogen and lower alkoxy; and R3 is hydrogen. Even still more preferably, R2 is halogen, preferably fluoro.
A preferred group of compounds includes:
(Z)-5-Fluoro-2-methyl-1-(2,4,6-trimethoxybenzylidene)-3-(N-benzyl)-indenylacetamide;
(Z)-5-Fluoro-2-methyl-1-(3,4,5-trimethoxybenzylidene)-3-(N-benzyl)-indenylacetamide;
(E)-5-Fluoro-2-methyl-1-(3,4,5-trimethoxybenzylidene)-3-(N-benzyl)-indenylacetamide;
(Z)-5-Fluoro-2-methyl-1-(2,3,4-trimethoxybenzylidene)-3-(N-benzyl)-indenylacetamide; and
(Z)-5-Fluoro-2-methyl-1-(2,4,5-trimethoxybenzylidene)-3-(N-benzyl)-indenylacetamide.
Preferred compounds are (Z)-5-fluoro-2-methyl-1-(3,4,5-trimethoxybenzylidene)-3-(N-benzyl)-indenylacetamide and the corresponding E-isomer. The most preferred compound is (Z)-5-fluoro-2-methyl-1-(3,4,5-trimethoxybenzylidene)-3-(N-benzyl)-indenylacetamide.
The present invention also is a method of treating a patient with precancerous lesions by administering to a patient a pharmacologically effective amount of a pharmaceutical composition that includes a compound of formula I, wherein R1 through R8 are as defined above. Preferably, this composition is administered without therapeutic amounts of an NSAID.
The present invention is also a method of treating individuals with precancerous lesions by administering a pharmacologically effective amount of an enterically coated pharmaceutical composition that includes compounds of this invention.
Also, the present invention is a method of inhibiting the growth of neoplastic cells by exposing the cells to an effective amount of compounds of formula I, wherein R1 through R8 are defined as above.
In still another form, the invention is a method of inducing apoptosis in human cells by exposing those cells to an effective amount of compounds of formula I, wherein R1 through R8 are defined as above where such cells are sensitive to these compounds.
Additionally, in yet another form, the invention is a method of treating a patient having a disease which would benefit from regulation of apoptosis by treating the patient with an effective amount of compounds of formula I, wherein R1 through R8 are defined as above. The regulation of apoptosis is believed to play an important role in diseases associated with abnormalities of cellular growth patterns such as benign prostatic byperplasia, neurodegenerative diseases such as Parkinson""s disease, autoimmune diseases including multiple sclerosis and rheumatoid arthritis, infectious diseases such as AIDS, and other diseases, as well.
As used herein, the term xe2x80x9cprecancerous lesionxe2x80x9d includes syndromes represented by abnormal neoplastic, including dysplastic, changes of tissue. Examples include adenomatous growths in colonic, breast, bladder or lung tissues, or conditions such as dysplastic nevus syndrome, a precursor to malignant melanoma of the skin. Examples also include, in addition to dysplastic nevus syndromes, polyposis syndromes, colonic polyps, precancerous lesions of the cervix (i.e., cervical dysplasia), prostatic dysplasia, bronchial dysplasia, breast, bladder and/or skin and related conditions (e.g., actinic keratosis), whether the lesions are clinically identifiable or not.
As used herein, the term xe2x80x9ccarcinomasxe2x80x9d refers to lesions that are cancerous. Examples include malignant melanomas, breast cancer, prostate cancer and colon cancer.
As used herein, the term xe2x80x9cneoplasmxe2x80x9d refers to both precancerous and cancerous lesions.
As used herein, the term xe2x80x9chaloxe2x80x9d or xe2x80x9chalogenxe2x80x9d refers to chloro, bromo, fluoro and iodo groups, and the term xe2x80x9calkylxe2x80x9d refers to straight, branched or cyclic alkyl groups and to substituted aryl alkyl groups. The term xe2x80x9clower alkylxe2x80x9d refers to C1 to C8 alkyl groups.
Compounds of this invention may be formulated into compositions together with pharmaceutically acceptable carriers for oral administration in solid or liquid form, or for rectal administration, although carriers for oral administration are most preferred.
Pharmaceutically acceptable carriers for oral administration include capsules, tablets, pills, powders, troches and granules. In such solid dosage forms, the carrier can comprise at least one inert diluent such as sucrose, lactose or starch. Such carriers can also comprise, as is normal practice, additional substances other than diluents, e.g., lubricating agents such as magnesium stearate. In the case of capsules, tablets, troches and pills, the carriers may also comprise buffering agents. Carriers such as tablets, pills and granules can be prepared with enteric coatings on the surfaces of the tablets, pills or granules. Alternatively, the enterically coated compound can be pressed into a tablet, pill, or granule, and the tablet, pill or granules for administration to the patient. Preferred enteric coatings include those that dissolve or disintegrate at colonic pH such as shellac or Eudraget S.
Pharmaceutically acceptable carriers include liquid dosage forms for oral administration, e.g., pharmaceutically acceptable emulsions, solutions, suspensions, syrups and elixirs containing inert diluents commonly used in the art, such as water. Besides such inert diluents, compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, and sweetening, flavoring and perfuming agents.
Pharmaceutically acceptable carriers for rectal administration are preferably suppositories which may contain, in addition to the compounds of this invention excipients such as cocoa butter or a suppository wax.
The pharmaceutically acceptable carrier and compounds of this invention are formulated into unit dosage forms for administration to a patient. The dosage levels of active ingredient (ie., compounds of this invention) in the unit dosage may be varied so as to obtain an amount of active ingredient effective to achieve lesion-eliminating activity in accordance with the desired method of administration (i.e., oral or rectal). The selected dosage level therefore depends upon the nature of the active compound administered, the route of administration, the desired duration of treatment, and other factors. If desired, the unit dosage may be such that the daily requirement for active compound is in one dose, or divided among multiple doses for administration, e.g., two to four times per day.
The pharmaceutical compositions of this invention are preferably packaged in a container (e.g. a box or bottle, or both) with suitable printed material (e.g., a package insert) containing indications, directions for use, etc.
The foregoing may be better understood from the following examples, that are presented for purposes of illustration and are not intended to limit the scope of the invention. As used in the following examples, the references to substituents such as R, R1, R2, etc., refer to the corresponding compounds and substituents in the formula I above.